Cardiac Ultrasound
Echocardiogram- Cardiac Ultrasound
Echocardiography is also referred to as cardiac ultrasound, or Echo. An Echocardiogram is a test used to assess the hearts’ function and structures.
This test is performed by a specially trained technician. It is a painless test that uses high frequency sound waves to generate pictures of your heart. During the test, you generally lie on your left side or back and gel is applied to your skin to increase the conductivity of the ultrasound waves. A technician then moves the small, plastic transducer over your chest to visualise the heart from different parts of the chest. The machine then analyses the information and develops images of your heart. These images are seen on a monitor and digitally recorded.
Echocardiography can help in the diagnosis of many heart problems including cardiovascular disease, previous heart attacks, valve disorders, weakened heart muscle, holes between heart chambers, fluid around the heart (pericardial effusion), and abnorml heart rhythms.
Transthoracic Echocardiogram -TTE
This is the most common type of echocardiogram, which uses ultrasound to look at the size and function of the heart, taking still or moving images of the internal parts of the heart. It is used for a non-invasive assessment of the overall health of the heart. An echocardiogram is used to evaluate all four chambers of the heart, the strength of the heart, the degree of contraction of the heart muscle, the condition of the heart valves, the lining of the heart (the endocardium), and the aorta. It can be used to detect any weaknesses or abnormalities of structure or function of your heart.
During the TTE (Echo) you will lie on your left side. The sonographer will apply gel to your chest wall and will press a probe (ultrasound transducer) against your chest to obtain images and to view your heart. The images are displayed in real time on the monitor and are also recorded. The technician will move the transducer to different areas on your chest that provide specific views of the heart.
The room will be darkened to help the sonographer view the images on the monitor. At times they will get you to breathe in and out, and hold your breath.
The examination takes approximately 45-60mins.
Bubble contrast TTE
This involves the injection of agitated saline into a vein, followed by an echocardiographic study. The bubbles are initially detected in the right atrium and right ventricle. If bubbles appear in the left heart, this may indicate a shunt – a movement of blood from the right side of the heart straight through to the left side , such as a patent foramen ovale, atrial septal defect, ventricular septal defect or arteriovenous malformations in the lungs.
Dobutamine Stress Echocardiogram -DSE
What is a Dobutamine Stress Echo?
A Dobutamine Stress Echo (DSE) combines a normal echo with the introduction of the drug (Dobutamine), which has similar effects to exercise on the heart and circulation. It works by increasing the heart rate and the strength of its contractions without the need for exercise.
Performing an echo during exercise can help doctors to find the cause of the symptoms you may experience during physical stress or exercise. It is sometimes difficult to get high-quality pictures of your heart during exercise because of deep breathing and movement. Some patients are also unable to do the exercise (stress) echo due to problems walking on a treadmill, so an alternative is to use Dobutamine.
Possible reasons for getting a Dobutamine Stress Echocardiogram (DSE) may include:
- To assess the heart’s function and structures
- To further assess the degree of known heart valve disease
- To determine limits for safe exercise before you start a cardiac rehabilitation program or are recovering from a cardiac event, such as a heart attack (myocardial infarction, or MI) or heart surgery
- To evaluate the cardiac status before heart surgery
What happens?
Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure. You will then be asked to sign a consent form that gives your permission to do the test.
We will ask you to remove your clothes from the waist up, put on a hospital gown and to lie on an echo bed. Small electrodes are placed on your chest to monitor the rate and rhythm of your heart, ECG. Your blood pressure will also be monitored throughout the examination.
A small plastic tube (cannula) will be inserted into a vein in your arm. We will take the first echo and then inject a very low dose of Dobutamine through the cannula. We will increase the drug in small doses every three minutes. During the test, you will gradually notice your heart beating faster and more strongly as if you were exercising. During the infusion your blood pressure, heart rate and rhythm will be closely monitored.
At regular intervals, the nursing staff will ask how you are feeling. Please tell them if you feel chest, arm, or jaw pain or discomfort, shortness of breath, dizzy, lightheaded or any other unusual symptoms.
Once you have reached your target heart rate (calculated based upon your age), the drug will be stopped. The doctor may also stop the drug early if you develop certain symptoms such as chest discomfort, shortness of breath, weakness, dizziness, or there are significant changes in your blood pressure or ECG.
Ultrasound images will be taken at all the stages throughout the test. Once all images are obtained the drug infusion will be cease and your heart rate will return to your normal resting rate. The effects of the drug will wear off in around 5 minutes.
Preparation for Dobutamine Stress Echo
Once your appointment has been made, the MCVS Patient Co-Ordinator will notify you of your admission time and discuss preparation with you. This will include having nothing to eat for 2 hours prior to your admission. You can continue to drink water only until admission time. If you are taking any Metoprolol / Bisoprolol or Betaloc – please let the Co-ordinator know, as you will need to stop taking this medication prior to the test.
What are the risks of having the test?
There are no known serious risks from the clinical use of ultrasound for scanning. The Dobutamine (stress) test is very safe and widely used in patients with chest pain or patients with symptoms that limit their ability to exercise.
A small number of patients may experience flushing of the face and / or minor palpitations, both of which go away very quickly once the test is stopped. You may also notice symptoms that you would otherwise have developed during normal exercise, such as chest pain, breathlessness, or dizzy spells, which usually go away once the test is stopped.
Dobutamine Stress Echo is widely used in patients with suspected or existing coronary artery disease. There is a very small risk of serious side effects such as heart attack or stroke in these patients and the medication can cause heart rhythm disturbance. Fortunately, serious side effects are very rare.
What happens after a Dobutamine Stress Echocardiogram?
You may resume your usual diet and activities unless your physician advises you differently.
Generally, there is no special type of care following a dobutamine stress echocardiogram. However, your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.
The test takes about one hour but you will stay in the Cardiac Day ward for 20-30minutes post procedure. Once you feel recovered, you can usually go straight home, but you are not permitted to drive for the rest of the day after the test.
Transoesophageal Echo – TOE
TOE is an alternative way to perform an echocardiogram. A specialized long flexible probe with an ultrasound transducer at its tip, is passed into the oesophagus. This gives high quality images, particularly of the back of the heart as this area lies right in front of the oesophagus. This enables accurate recording of flow in the heart and through the heart valves.
It is performed to diagnose valve disease, patent foramen ovale, atrial and ventricular septal defects, tumors and presence or absence of clot in the Atrial appendage.
During the TOE a Bubble Study test, may also be performed, to check for a small hole in the wall between the atria of the heart (called a Patent Foramine Ovale, PFO). This involves the injection of saline filled with tiny bubbles into a vein in the arm. Normally the lungs simply filter out the bubbles. However if there is a tiny opening in the wall between the atria (the upper chambers of the heart), the bubbles will move from the right side of the heart through the opening and will be seen on the ultrasound, on the left side of the heart.
To be able to tolerate the procedure you will be given sedation and your throat will be sprayed with local anaesthetic and you will usually be asked to gargle it. Your ability to swallow afterwards will be tested and you should not have very hot food or beverages to swallow in case of burning.
It is important to note that you cannot drive for 24 hours following the sedation given and that you should have someone stay with you overnight.
The study should take approximately 30 – 60 minutes.